Fuse box



E. A. HORN Aug. 24, 1937.

FUSE BOX Filed Feb. 24, 1956 'INVENTOR EMIL A. HDRN BY HIS ATTORNEYSPatented Aug. 24, 1937 UNITED STATES PATENT OFFICE FUSE BOX tion of NewYork Application February 24, 1936, Serial No. 65,485

3 Claims.

This invention relates to fuse boxes and more particularly those of themulti-fuse type, such for example as may be inserted in a three phasepower supply to electric power tools.

Objects of the present invention are to render the fuse box compact,particularly by reducing the height thereof; to render the sameconvenient, particularly by providing interchangeable and reversiblefuse carriers; to simplify assembly, particularly by reducing the numberof parts and eliminating loose parts such as nuts; and to facilitateconnections to the fuse box by providing conveniently accessible bindingposts there for.

Other objects will be apparent from the following description, withreference to the accompanying drawing, in which,

Figure 1 is a top plan view of the fuse box according to the preferredembodiment of the present invention, one of the fuse carriers or fusechamber covers being removed;

Figure 2 is an end elevation, partly in vertical section along the line2-2 of Figure 1, and partly exploded to show the fuse carrier removedfrom the fuse chamber; and

Figure 3 is a longitudinal vertical section taken I along the line 3-3of Figure 1.

The fuse box according to the present inven tion comprises a block ofmolded insulation having a fiat base 4 provided with upstanding endwalls 5 and 6, between which extend side walls I, 8, 9, and 10, thusdefining three fuse chambers or wells of rectangular contour. Anindividual cover l2 of the same material is provided for each of thefuse chambers, being slightly smaller than the same so as to be let downthereinto, whereby the top of the cover 12 is flush with the top of theside and end Walls of the respective chambers. A suitable handle 13,preferably of the same insulating material and rigid therewith, isprovided for each of the covers l2.

Each end of each chamber is provided with a substantially U-shapedcontact clip, having a fiat base I4 resting on the bottom of the chamberconstituted by the top of the base 4. Each of these contact clipscomprises a pair of upstanding divergent arms I5 which are concavetoward each other and terminate in further divergent top portions 16.

Cooperating with these contact clips are fuse clips secured to therespective ends of each fuse chamber cover l2. Each of these fuse clipscomprises a flat base I! having depending arms l8 concave toward eachother. These arms are bent 55 upwardly and inwardly as at I 9 and areconcave toward each other as at 2G, to receive therebetween the metalend cap 2!' of a cartridge fuse. The fuse clips are each secured to thecover it! by a screw 22 passing through the base i? thereof, thusforming therewith a carrier for the fuse.

It will be readily apparent from an inspection of Figure 2, that thefuse carrier clips are thinner and are therefore less rigid than thecontact clips, although both are of resili nt conducting material. Henceas the cover i2 is moved downward, the concave side walls i8 passbetween the divergent clip ends it and are cammed inwardly thereby. Thefolds !9 are thus drawn toward each other, and as the concave fuseengaging portions 20 are free at their inner ends, these are wipeddownwardly around the fuse cap 2| therebetween. This wiping action tendsto insure adequate contact.

As the cover 12 is moved further downwardly, the widest point of thearms l8 passes the narrowest point or throat between the arms 55, andthereafter the resilience and shape of the cooperating clips causes asort of snap action which brings the clips together in interfittingcontact, and thereby brings the top of the cover I2 flush with the topof the fuse box.

The snap action, however, does not entirely release the compression ofthe fuse clip. In this closed position the arms l8 are still compressedtoward each other by and between the arms IS, with the result that theportions 20 maintain the fuse caps under additional pressure, and thefuse cannot escape. Furthermore, when the cover is removed, carrying thefuse clips and the fuse with it, accidential displacement of the fuse isprevented by the residual initial compression of the portions 20, whichextend around and engage under pressure the greater part of theperiphery of the fuse caps.

For connecting the contact clips into the circuit to be protected, aconductor strap 23 is provided at each end of each fuse chamber. Thesestraps 23 pass through the end walls 5 and 6, respectively, theapertures 3'! therefor being molded upwardly through the base 4.

The inner end of the conductor strap 23 overlies the base [4 of thecontact clip, and is punched upwardly and tapped as at 24, over acentral aperture in the base M, to receive an assembly screw 25, whichis inserted through a suitable shouldered aperture 26 in the base 4,thus securely clamping the base M of the contact clip therebetween,after which the apertures 26 are plugged with sealing wax or the like.The outer end of the strap 23 is laterally flanged upwardly as at 3!,and is centrally punched downwardly and tapped to receive a screw 27which serves as a binding post.

It should be noted that the base 4 is extended longitudinally at eachend forming an extension 28, and the strap 23 overlies the same. Theextension 28 is apertured as at 29 to provide clearance for the lowerend of the binding post 21. Also, short buttresses 38 are provided,aligned with the side walls 7, 8, 9, and Hi. Thus the extensions 28 andthe buttresses 3Q provide individual pockets separating and insulatingthe binding posts El, but as these pockets are open at the top and end,they are convenientlyacces sible for connecting wires to the bindingposts. a

The based is provided with apertures 36 for receiving bolts or screws tosecure the same to a wall or other support. In the form shown, theseapertures 36 are countersunk and provided one in the bottom of each ofthe fuse chambers. Thus even though the fuse boxes were to be bolteddirectly to a metal support, the live connections would be adequatelyinsulated therefrom, particularlythe binding posts 2?, and as these areexposed at the top, they are readily accessible without removing thefuse box from its support.

To provide a rigid attachment for the knob 13, .a tapped metal insert 3iis embedded or molded therein. This insert is partly cylindrical, buthas square ends, the lower one of, which extends into a square recess inthe top of cover l2. A screw 32 is inserted upward through a shoulderedcentral aperture in the cover l2 into the tapped bore of the insert 3i.7

The lower side of the cover I2 is of reduced thickness, or-channeledtransversely at each end, and the center of each end is further reducedor channeled longitudinally, forming a square'recess 3d receiving thefuse clip base H. A tapped and knurled insert 33 is embedded or moldedcentrally in the cover l2 above each such recess, to receive the screw22' securing the base i! thereto. Although theupper ends of the concaveportions 253 are close together, the resilience of the fuse clip issufficient to permit entrance and turning of a screw driver forinstalling the screw 22. The aperture of the insert 32 is continued openup through the cover 52 as at 35, to receive points for engaging thescrews 22 and thus testing the fuses without removing the covers.

I claim:

1. A fuse box comprising'a block of molded insulation having a base withend walls and side walls defining a fuse chamber, a contact clip at eachend of said chamber having a pair of divergent arms extending upwardlytherein and concave toward each other, a cover for said chamher havingdepending fuse clips at each end thereof with blades concave toward eachother and receiving one end of the fuse therebetween, and portionsoutside thereof spaced therefrom substantially concentric therewith andhaving convex outer surfaces, said fuse clips'being of spring materialfor greater yielding thereof than said contact clips so as to snap intointerfitting cont-act therewith when the cover' is closed, with theconcave surfaces of said contact clips and the convex surfaces of saidfuse clip portions in interof both. e

2. In a device of the character described, a relatively rigid contactclip comprising a pair of upstanding divergent arms which are concavetoward each other, and a relatively yieldable fuse clip comprisingdepending arms concave toward. each other and bent upwardly and inwardlyand again concave toward each other to receive between the inner concaveportions the end cap of a cartridge fuse, the outer portions of saidfuse clip being adapted to enter the concave portions of said contactclip and contact the same alon a common curvature throughout the greaterpart of their respective lengths.

S. In a three phase fuse boX having a base with two end walls and fourside walls therebetween defining a plurality of parallel fuse chambers,a contact clip at each end of each chamber formed of a strip ofreiatively thick and rigid sheet metal and comprising a base and a pairof upstanding arms concave toward each other but diverging at theirtops, a separate cover for each chamber 7 having at each end a fuse clipformed of a strip of relatively thin and yieldable sheet metal andcomprising depending arms concave toward each other and bent upwardlyand inwardly and again concave toward each other to receive between theinner concave portions thereof the end cap of a cartridge fuse, theouter portions of said fuse clip on the cover being smoothly convex andadapted to yield upon entering said relatively rigid divergent tops ofsaid chamber contact clip and cause said inner concave portions of thefuse clip in engagement with the fuse end cap to have a wiping actionwith respect to said fuse end cap, said outer portions of said fuse clipon the cover being smoothly convex andadapted upon further entry intosaid chamber contact clip to contact the same along a common curvaturethroughout the greater part of their respective lengths.

EMIL A. HORN.

. fitting contact for the greater part of the depth 7 ill

